Volvo: Volvo running/electrical issue, volvo 740 gl, dashboard lights

Question
I have a 1990 Volvo 740 Gl, about 165,00 miles. Recently( last couple months) the car had trouble starting and then  staying running. I just thought the car was getting old and being stubborn in the cold. Car would stall at low rpms. Changing from park to reverse or drive, turning in parking lots, etc. Then about 2 weeks ago while driving, the battery, oil and other dashboard lights would start to fade on and off. and the car would feel like it was going to stall at low rpms, and sometimes did. As long as I kept the engine revving it would kinda of go away.

I finally took it to a mechanic but they said they couldn't diagnose the problem and that i needed to take it to a volvo dealer to plug it in to the computer. But they thought it could be the air mass sensor. I ordered one off ebay and took 5 minutes to install it. Car seemed to run a lot better and more smoothly. But the dash lights would still fade on/off but the car didn't so much as hiccup. This was last thursday.

Sat while going to my buddies place the car was running fine, then most of the way there the SRS light came on, then my radio completely shut down, the interior lights and headlamps were pretty dim, then the car abolutely died on the off ramp. Completely dead not a click. Had it towed to my buddies place and dealt with it today.

Got it jumped, started immediately and tried to get home. Made it part way and same thing happened only quicker. Had a friend bring me a new battery, threw it in and started right up and made it home.

I went to the gym tonight and now only the dash lights keep wanting to fade on/ off. And when i turn the key to the engaged position but not on, only the oil light and 1 other light up. No service engine, brake or other lights that should normally light up. What do you think the problem is/ what should i do????
PS sorry for the long letter but i thought as much info would be helpfull.  -Lou

Answer
Lou,
Test the charging system and pay attention to the crank pulley, they seperate and will not spin as fast as the engine and will not put a charge into the battery. If that pulley is ok make sure the charging system works and charges, maybe the regulator is going out, or maybe the alt is weak and not able to charge the battery.